Sorry, the assertion should be

DBUG_ASSERT(table->file == this || dynamic_cast<ha_innobase*>(table->file) == NULL);

Well, the tests seem passing after adding this assertion (and a similar one for myisam):

https://github.com/MariaDB/server/commit/f221bc46e6981c9e7c5d2806faefb1ed086e7bf8

Okay, I think I can agree on this approach, but then I want these assertions to be committed as well.

dynamic_cast can be replaced with hton comparison, of your choice.

Maybe somebody later will need row changes from a separate handler, imagine for example cascade

foreign key updates, which would have used a lookup handler for the cascade changes. For that case,

I'll try to gather these table->file comparisons under a single method.

Alternatively, we could introduce some bool handler::root_handler just now, without waiting for a demand,

but I'm afraid it could become another source for bugs. So better later on demand.

On Mon, 8 May 2023 at 22:49, Sergei Golubchik <serg@mariadb.org> wrote:

Hi, Nikita,

On May 08, Nikita Malyavin wrote:
> On Fri, 5 May 2023 at 20:46, Sergei Golubchik <serg@mariadb.org> wrote:
>
> > > #ifdef HAVE_REPLICATION
> > > - if (unlikely(!error && table->s->online_alter_binlog))
> > > + if (unlikely(!error && table->s->online_alter_binlog &&
> > > + !table->skip_online_logging))
> >
> > this doesn't need any juggling with skip_online_logging.
> > This problem is already solved for, say, long uniques. You can use
> >
> > this == table->file
> >
> > condition to filter out individual partitions and have your
> > binlog_log_row_online_alter called only for the main ha_partition
> > handler.
>
> This doesn't look reliable -- won't there be any cases when we make a
> change from another handler, not table->file?

So far, that's how it works - updates come through table->file

> If that never happens, we could add DBUG_ASSERT(this == table->file) in
> ha_innodb's/ha_myisam's ha_*_row methods.

Of course, not. That's the whole point. The server calls
ha_partition::ha_write_row, which calls, in turn,
ha_innodb::ha_write_row. For individual partitions this != table->file,
that's how we make sure that certain code (e.g. long unique checks) are
only run once and not repeated per partition.

Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org

Yours truly,

Nikita Malyavin